The St. Louis-Cape Girardeau CCOP is a consortium of five hospitals in two separate bi-state health service areas in eastern Missouri and western Illinois. The Investigators from the St. Louis Metropolitan area, which includes Alton, Illinois, are affiliated with one or more of three hospitals in the consortium and have worked together for the past fifteen years in cancer treatment research protocols and more recently, in cancer control research studies. The Cape Girardeau Investigators have worked with CCOP for the past nine years and are affiliated with two hospitals in that city. During the next five years we expect to accrue at least eighty credits per year for cancer treatment research protocols of the NSABP and SWOG and at least seventy five credits (new participants and follow-up) per year for cancer control and prevention studies. These cancer control credits will be derived primarily from our participation in the Breast Cancer Prevention Trial-1, Prostate Cancer Prevention Trial-1 and the Breast Cancer Prevention Trial-2 provided we are chosen as a site. We will continue to provide high quality data to the Southwest Oncology Group and the National Surgical Adjuvant Breast Program which are our research bases, utilizing the data management system developed during the past fifteen years. In summary, we will continue our excellent performance of the last fifteen years in cancer treatment research studies and extend our more recent participation in cancer control and prevention trials as well. The past experience and capabilities of the Investigators and Clinical Research Associates provides a strong base for continuing development of this Community Clinical Oncology Program.